Conventionally, Patent Document 1 discloses the technology of mounting an airbag device to a steering wheel.
According to Patent Document 1, pins are provided to any one of a base plate that supports a back body to be inflated and deployed and a steering wheel. A lock groove, which has an opening with an approximately trapezoidal-shaped cross section in side view and a width gradually increasing toward the opening direction, is formed in the pin. In addition, mounting parts into which the pins can be inserted are provided in the other of the base plate and the steering wheel. A switch wire serving as a lock member is mounted to the mounting parts. Then, the pins are inserted into the mounting parts, whereby the switch wire is engaged with the engaging grooves of the pins, which keeps the state in which the base plate and the steering wheel are installed, that is, the state in which the airbag device is mounted.